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Landscape Ecological Potential Author: JL Weber et al., EEA Discussant: Lars Hein, Wageningen University. Contents. Introduction to NLEP Observations from the Discussant Questions for discussion. Why ?.
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Landscape Ecological Potential Author: JL Weber et al., EEA Discussant: LarsHein, Wageningen University
Contents • Introduction to NLEP • Observations from the Discussant • Questions for discussion
Why ? • Ecosystem accounting needs to be based on (among others) physical accounts of ecosystems and the benefits they provide • Ecosystems, unfortunately, are very complex, diverse, and difficult to define and delineate. • Simplified approach needed as a basis for physical (ecosystem) accounting • Is this simplified approach the ‘Net Landscape Ecological Potential’ ?
What ? • Net Landscape Ecological Potential (NLEP) developed by EEA (‘Net Landscape Ecological Potential of Europe and change 1990-2000’ – authors: JL Weber, R. Spyropoulou, T. Soukup, F. Paramo, April 2008) • NLEP = Composite indicator for ecosystem integrity at the macro scale • Developed by EEA for Europe for 1990 and 2000. • Changes in NLEP reflect degradation or rehabilitation of ecosystems
How ? • NLEP = f (vegetation cover, protected status, fragmentation)
Vegetation Cover: Green Background Index (0-100) • Aggregation (and smoothing) of forests, pasture, inland waters, wetlands, semi-natural land and agricultural mosaics. Equal weighting ?
Protected status (Naturalis Index) (0-100) • Protected status, on the basis of designated sites (e.g. Natura2000, Ramsar) + high ecological value close to protected site (<5 km)
Fragmentation (0-255) • Reflects barriers to wildlife from roads, railways and constructions. The more barriers the lower the index value. Log conversion.
Combined into: NLEP (0 to 255) • GLEP = Green background Index + Naturalis Index (stretched from 0 to 255 ?) • NLEP = sqrt (GLEP * Fragmentation index)
Observations on the Methodology (1) • Heavy weighting of Fragmentation, around twice as much impact as vegetation or protected status. • Not all species strongly affected by fragmentation (e.g. birds) • Some choices appear subjective (log transformation of fragmentation, choice of 5 km form protected areas, equal aggregation of specific habitat types in the greenness maps) • Why is fragmentation the difference between net and gross LEP ?
Observations on the Methodology (2) • No embedding of bottom-up / national data (e.g. EBONE Project / GEO)
Observations on the Methodology (3) • Index does not allow to analyse ecosystem or species diversity at a European scale (e.g. index may remain the same even if all wetlands are lost if this is compensated by forests)
Observations on the Methodology (4) • NLEP proposed as proxy for ecosystem integrity (defined as ability of ecosystems to support biological communities comparable to natural habitat) • Ecosystem use not reflected in the NLEP, but NLEP may reflect the potential to supply ES. • Relation between ecosystem integrity and the supply of (all?) ecosystem services unclear.
Discussion questions • Is the NLEP a correct indicator for ecosystem integrity ? • how can it be improved ? • Will a reduction in NLEP lead to a loss of ES supply ? • Can NLEP be used to reflect the supply of some ecosystem services ? • CAN NLEP serve the creation of physical accounts ? • Should we have a top-down approach (such as NLEP) or have a bottom-up approach (starting with ES supply and linking those to ecosystem properties) , or is there scope to test both approaches ? • Where to go from here in defining ecosystem units/properties in support of establishing physical accounts ? • What other questions do you have ?
Question 1 • Is the NLEP a correct indicator for ecosystem integrity ? • how can it be improved ?
Question 2 • Will a reduction in NLEP lead to a loss of ES supply ? • Can NLEP be used to reflect the supply of some ecosystem services ?
Question 3 • CAN NLEP serve the creation of physical accounts ? • Should we have a top-down approach (such as NLEP) or have a bottom-up approach (starting with ES supply and linking those to ecosystem properties) , or is there scope to test both approaches ?
Question 4 • Where to go from here in defining ecosystem units/properties in support of establishing physical accounts ?
Ecosystem change is complex • Source of figures: Scheffer et al., 2001. Ecosystem models developed in Weikard and Hein, in press (Threshold); Hein, 2006 (Hysteresis) & Hein and Van Ierland, 2006 (Irreversible change). Gradual change Threshold Hysteresis Irreversible change